(a) Field of the Invention
This invention relates to a wireless telephone system and more particularly, but not by way of limitation, to a system for expanding the geographic coverage of a cell site operating signal foot-print. More specifically, the system is designed to reproduce a wireless base station's signal foot-print and introduce the cloned foot-print into new geographical areas to the benefit of cellular telephone users.
(b) Discussion of Prior Art
In today's wireless telephone market there are several units which produce coverage other than a wireless base station site. The units are used for expanding wireless signal coverage and are described as follows:
Fiber optic micro cell site: This type of site produces its own frequencies that are different from adjacent cell sites. Each sites primary function is to introduce low-power cellular signal footprints into small geographical areas that don't have a need for a high-power signal footprint.
Bi-directional amplifier: This type of unit re-radiates operating frequencies at a composite output power of 3 watts maximum. This means that multiple carriers are reduced to powers in a milli-watt range.
Cell extender: This unit is limited to communicating only to a donor cell. The cell extender can produce equal power but operates at different frequencies and is limited to a maximum of 10 channels. Also, the cell extender ties up channel banks within the cellular base station, making it a very inefficient operating system.
In U.S. Pat. No. 5,187,806 to Johnson et al. an apparatus and method for expanding cellular system capacity is disclosed. This system uses a cell site transceiver and a remote site transceiver to extend a cell site to a remote location within a geographic sector. The patents cited in U.S. Pat. No. 5,187,806 are incorporated herein by reference.
None of the above mentioned cellular systems provide a powerful, compact and easily transportable system that reproduces the same signal magnitude of its donor site and does not require the need to use channel banks. The subject invention speaks to adjacent cell sites as if it was a real, full-blown cell site itself. The adjacent cell sites don't know or see any difference in the cloning unit.